More Nuclear Reactors Called for to Ensure Uninterrupted Supply of Radioisotopes

by Gopalan on Jul 30 2008 11:59 AM

A Canadian panel has called for more nuclear reactors to be set up to ensure uninterrupted supply of radioisotopes and also a better communication mechanism among the agencies involved.

The shutdown of the National Research Universal nuclear reactor at Chalk River in November 2007 had sparked off a near crisis in the nuclear medicine community.

The reactor, which provides two-thirds of the world's radioisotopes, stopped supplying nuclear material essential for medical imaging and diagnostic scans for fractures, cancers and heart conditions. It was restarted on December 16.

A group of health specialists, including experts from the field of nuclear medicine, was convened by Health Canada in December 2007 during the prolonged shutdown. The group was conveying to the government its assessment of the impact of the isotope shortage. Once the reactor was restarted and the supply of medical isotopes returned to normal, the group began work on lessons learned from the situation.

In their report released Monday, the doctors write how they were in the dark when the Chalk River nuclear reactor halted production of medical isotopes late last year, a critical oversight that put patients at risk.

Doctors say they were forced to delay diagnostic and treatment procedures for patients across the country when the supply of isotopes dried up last December.

And not knowing how long the isotope shortage would last, they were forced to decide whether to proceed with other procedures for their patients that carried more risk or would be less accurate.

"For patients with serious and often life-threatening conditions, the lack of certainty was chilling," says the report titled Lessons learned from the shutdown of the Chalk River reactor.

"People scheduled for diagnostic tests received little or no information about how long they would have to wait or whether they would have the prescribed test at all," it said.

The crisis created "emotional stress and tension" at every level of the health-care system as the shortage "compromised" emergency services in some regions and forced some nuclear medicine departments to close completely, it said.

"For the longest time, it was a moving target and that makes it very difficult to figure out what to do. ... We didn't know how long it was going to last," Dr. Douglas Abrams, one of the authors of the report who works at the University of Alberta's Cross Cancer Institute. said in an interview.

The Chalk River facility was shut down by Atomic Energy of Canada Ltd. on Nov. 18 for routine maintenance. But the shutdown was unexpectedly prolonged after an inspection found that mandatory safety upgrades ordered by the Canadian Nuclear Safety Commission had not been done.

The report recommends ways to minimize the potential for shortages and to mitigate consequences for patients should a shortage occur, including better communications with doctors and the public and enhancing the capability of supplies to respond to shortages.

The report also suggests a reserve of raw materials should a shortage occur, and wants more reactors opened to create isotopes. "Canada needs reactors that are designed to expand their production capabilities quickly in response to an emergency," it reads.

It recommends that nuclear medicine facilities have access to back-up generators in emergency situations, that Health Canada fast track generator products that are currently not approved but might be useful, or that nuclear medicine facilities explore using partially spent generators or ones past their expiry dates if needed.

It also suggests that nuclear medicine facilities work overtime in cases where there are isotope shortages, to maximize usage of existing isotopes. "The nature of radioisotope generators is that 20 per cent of their capacity is lost every day," the report says.

Each week, 30,000 diagnostic tests and 300 therapeutic doses in Canada rely upon radiopharmaceuticals. They are used in a wide variety of medical applications such as locating tumors, monitoring results of cancer treatments, evaluating heart diseases and diagnosing thyroid diseases.

Health Canada, Natural Resources Canada and the Atomic Energy of Canada Limited have now put in place a communications plan to preclude another extended closure of the Chalk River reactor in the future, it has been stated.

Ironically only last May the AECL decided to scrap work on the Maple reactors that were designed to replace the Chalk River facility.

Conceived in the early-1990s, the Maples (which stands for Multipurpose Applied Physics Lattice Experiment) were supposed to start generating isotope feedstock in 2000 and 2001. But as a result of management, engineering and construction flaws, they have never worked well enough to get regulatory approval.

The two Maple reactors have burned through more than $300 million over 15 years in futile effort to replace the workhorse National Research Universal (NRU) reactor built in 1957.

AECL said it halted work following reviews of the costs of further development, the time frame and risks involved

"These were one-of-kind research reactors which morphed into production units and ultimately ended up in a bad place," AECL chief executive Hugh MacDiarmid said then.

It is now even more dependent on the 50-year-old NRU reactor at Chalk River for isotope feedstock.

The problems go to the heart of the nuclear medicine industy - a reliance on a handful of aging reactors in Canada, Europe and South Africa.

The public wants the isotopes which diagnose bone fracturers and heart disease and treat many cancers. But they don't want new nuclear reactors that produce the critical raw isotopes.

In addition, the reactors face increasingly tight regulation because of the risk that byproducts might be used by terrorists to make dirty bombs.

The result is relatively thin profit margins which make major new investments a difficult decision - even without the tough technical issues exposed in the Maples fiasco.

The short-shelf life of isotopes - typically three days or less - makes it impossible to stockpile for emergencies or to exploit competitor problems.

MacDiarmid said he believes that other reactors will be built in the next five years around the world, though probably not in Canada.

"Our analysis is that we are going to see an improvement in supply around the world."